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import "compiler/ast.cup"
import "std/file.cup"
let gen_out_file: File*;
let gen_label_counter = 0;
fn emit_asm4(msg1: char*, msg2: char*, msg3: char*, msg4: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
fwrite(gen_out_file, msg3, strlen(msg3));
fwrite(gen_out_file, msg4, strlen(msg4));
}
fn emit_asm3(msg1: char*, msg2: char*, msg3: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
fwrite(gen_out_file, msg3, strlen(msg3));
}
fn emit_asm2(msg1: char*, msg2: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
}
fn emit_asm(msg: char*) {
fwrite(gen_out_file, msg, strlen(msg));
}
fn emit_num(num: int) {
// FIXME: Just support printing negatives directly.
if (num < 0) {
emit_asm("-");
num = -num;
}
fputu(gen_out_file, num);
}
fn generate_syscall(num: int) {
emit_asm(" mov rax, "); emit_num(num); emit_asm("\n");
emit_asm(" syscall\n");
}
fn generate_expr_into_rax(node: Node*);
fn generate_lvalue_into_rax(node: Node*) {
if (node.typ == AST_LOCAL_VAR) {
let offset = node.d.variable.offset;
emit_asm(" mov rax, rbp\n");
emit_asm(" sub rax, "); emit_num(offset); emit_asm("\n");
} else {
die2("Unsupported type in generate_lvalue_into_rax: ", node_type_to_string(node.typ));
}
}
fn generate_function_call(node: Node*) {
let total_size = 0;
let n = node.d.call.args.size;
for (let i = n-1; i >= 0; --i) {
let expr: Node* = node.d.call.args.data[i];
generate_expr_into_rax(expr);
emit_asm(" push rax\n");
// TODO: this might be an issue if we pass structs some day
total_size = total_size + 8;
}
emit_asm3(" call func_", node.d.call.func.d.func.name, "\n");
emit_asm(" add rsp, "); emit_num(total_size); emit_asm("\n");
}
fn generate_expr_into_rax(node: Node*) {
if (node.typ == AST_LITERAL) {
if (node.etyp.typ == TYPE_INT) {
emit_asm(" mov rax, "); emit_num(node.d.literal.as_int); emit_asm("\n");
} else {
die("Unsupported literal type in generate_expr_into_rax");
}
} else if (node.typ == AST_CONDITIONAL) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.conditional.cond);
emit_asm(" cmp rax, 0\n");
emit_asm(" je .cond_els"); emit_num(label); emit_asm("\n");
generate_expr_into_rax(node.d.conditional.then);
emit_asm(" jmp .cond"); emit_num(label); emit_asm("\n");
emit_asm(".cond_els"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.conditional.els);
emit_asm(".cond"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_PLUS) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" add rax, rbx\n");
} else if (node.typ == AST_MINUS) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" sub rax, rbx\n");
} else if (node.typ == AST_DIV) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cqo\n");
emit_asm(" idiv rbx\n");
} else if (node.typ == AST_MOD) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cqo\n");
emit_asm(" idiv rbx\n");
emit_asm(" mov rax, rdx\n");
} else if (node.typ == AST_MUL) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" imul rbx\n");
} else if (node.typ == AST_EQ) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" sete al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_NEQ) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" setne al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_LT) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" setl al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_LEQ) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" setle al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_GT) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" setg al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_GEQ) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cmp rax, rbx\n");
emit_asm(" setge al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_BWAND) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" and rax, rbx\n");
} else if (node.typ == AST_BWOR) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" or rax, rbx\n");
} else if (node.typ == AST_XOR) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" xor rax, rbx\n");
} else if (node.typ == AST_BWINV) {
generate_expr_into_rax(node.d.unary);
emit_asm(" not rax\n");
} else if (node.typ == AST_NEG) {
generate_expr_into_rax(node.d.unary);
emit_asm(" neg rax\n");
} else if (node.typ == AST_NOT) {
generate_expr_into_rax(node.d.unary);
emit_asm(" cmp rax, 0\n");
emit_asm(" sete al\n");
emit_asm(" movzx rax, al\n");
} else if (node.typ == AST_OR) {
// With short circuiting!
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.binary.lhs,);
// If left is true, we can short-circuit
emit_asm(" cmp rax, 0\n");
emit_asm(" je .or_r"); emit_num(label); emit_asm("\n");
emit_asm(" mov rax, 1\n");
emit_asm(" jmp .or_e"); emit_num(label); emit_asm("\n");
emit_asm(".or_r"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.binary.rhs);
// Booleanize the result
emit_asm(" cmp rax, 0\n");
emit_asm(" setne al\n");
emit_asm(".or_e"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_AND) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.binary.lhs);
// If left is false, we can short-circuit
emit_asm(" cmp rax, 0\n");
emit_asm(" jne .and_r"); emit_num(label); emit_asm("\n");
emit_asm(" mov rax, 0\n");
emit_asm(" jmp .and_e"); emit_num(label); emit_asm("\n");
emit_asm(".and_r"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.binary.rhs);
// Booleanize the result
emit_asm(" cmp rax, 0\n");
emit_asm(" setne al\n");
emit_asm(".and_e"); emit_num(label); emit_asm(":\n");
} else if (is_lvalue(node.typ)) {
generate_lvalue_into_rax(node);
emit_asm(" mov rax, [rax]\n");
} else if (node.typ == AST_ASSIGN) {
generate_lvalue_into_rax(node.d.assign.lhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.assign.rhs);
emit_asm(" pop rbx\n");
emit_asm(" mov [rbx], rax\n");
} else if (node.typ == AST_FUNCCALL) {
generate_function_call(node);
} else {
die2("Unsupported node type in generate_expr_into_rax: ", node_type_to_string(node.typ));
}
}
fn generate_block(node: Node*);
fn generate_statement(node: Node*) {
if (node.typ == AST_RETURN) {
generate_expr_into_rax(node.d.unary);
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
emit_asm(" ret\n");
} else if (node.typ == AST_VARDECL) {
if (node.d.var_decl.init) {
generate_expr_into_rax(node.d.var_decl.init);
let offset = node.d.var_decl.var.offset;
emit_asm(" mov [rbp-"); emit_num(offset); emit_asm("], rax\n");
}
} else if (node.typ == AST_BLOCK) {
generate_block(node);
} else if (node.typ == AST_IF) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.conditional.cond);
emit_asm(" cmp rax, 0\n");
emit_asm(" je .els"); emit_num(label); emit_asm("\n");
generate_statement(node.d.conditional.then);
emit_asm(" jmp .if"); emit_num(label); emit_asm("\n");
emit_asm(".els"); emit_num(label); emit_asm(":\n");
if (node.d.conditional.els)
generate_statement(node.d.conditional.els);
emit_asm(".if"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_WHILE) {
let label = ++gen_label_counter;
emit_asm(".loop_s"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.looop.cond);
emit_asm(" cmp rax, 0\n");
emit_asm(" je .loop_e"); emit_num(label); emit_asm("\n");
generate_statement(node.d.looop.body);
emit_asm(" jmp .loop_s"); emit_num(label); emit_asm("\n");
emit_asm(".loop_e"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_FOR) {
let label = ++gen_label_counter;
if (node.d.looop.init)
generate_statement(node.d.looop.init);
emit_asm(".loop_s"); emit_num(label); emit_asm(":\n");
if (node.d.looop.cond) {
generate_expr_into_rax(node.d.looop.cond);
emit_asm(" cmp rax, 0\n");
emit_asm(" je .loop_e"); emit_num(label); emit_asm("\n");
}
generate_statement(node.d.looop.body);
if (node.d.looop.step)
generate_statement(node.d.looop.step);
emit_asm(" jmp .loop_s"); emit_num(label); emit_asm("\n");
emit_asm(".loop_e"); emit_num(label); emit_asm(":\n");
} else {
// Default to a simple expression statement
generate_expr_into_rax(node);
}
}
fn generate_block(node: Node*) {
let n = node.d.block.children.size;
for (let i = 0; i < n; ++i) {
generate_statement(node.d.block.children.data[i]);
}
}
fn generate_function(node: Node*) {
emit_asm3("global func_", node.d.func.name, "\n");
emit_asm3("func_", node.d.func.name, ":\n");
emit_asm(" push rbp\n");
emit_asm(" mov rbp, rsp\n");
emit_asm(" sub rsp, "); emit_num(node.d.func.max_locals_size); emit_asm("\n");
generate_block(node.d.func.body);
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
emit_asm(" ret\n");
}
fn generate_program(ast: Node*, file: File*) {
gen_out_file = file;
let n = ast.d.block.children.size;
for (let i = 0; i < n; ++i) {
let node: Node* = ast.d.block.children.data[i];
if (node.typ == AST_FUNC) {
generate_function(node);
} else {
die("Unknown node type in generate_program");
}
}
if (OS_IS_MACOS) {
emit_asm("global _main\n");
emit_asm("_main:\n");
// Push argv
emit_asm(" mov rax, rsi\n");
emit_asm(" push rax\n");
// Push argc
emit_asm(" mov rax, rdi\n");
emit_asm(" push rax\n");
} else {
emit_asm("global _start\n");
emit_asm("_start:\n");
emit_asm(" mov rbp, rsp\n");
// // Push argv
emit_asm(" mov rax, rbp\n");
emit_asm(" add rax, 8\n");
emit_asm(" push rax\n");
// Push argc
emit_asm(" mov rax, [rbp]\n");
emit_asm(" push rax\n");
}
emit_asm(" call func_main\n");
emit_asm(" mov rdi, rax\n");
generate_syscall(SYS_exit);
}
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